As is well known, signal predistortion techniques are used in conjunction with power amplification in order to correct for undesirable effects, such as output signal distortion, spectral regrowth and adjacent channel power (ACP), that are typically associated with amplifier nonlinearity at high output power levels. In general, predistortion techniques involve distorting an input signal prior to amplification in a manner that takes into account the transfer function characteristics of the amplifier, such that the nonlinearity-related effects are at least partially canceled out in the resulting output signal.
Recently-developed signal predistortion techniques which overcome one or more problems associated with conventional techniques are described in U.S. patent application Ser. No. 09/915,042, filed Jul. 25, 2001 and entitled “System and Method for Predistorting a Signal Using Current and Past Signal Samples,” and U.S. patent application Ser. No. 09/928,628, filed Aug. 13, 2001 and entitled “Multiple Stage and/or Nested Predistortion System and Method,” now issued as U.S. Pat. No. 6,931,080, both of which are hereby incorporated by reference herein.
Despite the considerable advances provided by the predistortion techniques described in the above-cited U.S. patent application Ser. Nos. 09/915,042 and 09/928,628, a need remains for further improvements in predistortion techniques, so as to provide additional performance enhancements in wireless communication systems and other systems employing power amplification.